A blunt object commonly known as a bluff body immersed in a stream of flowing fluid generates and sheds natural vortices from two sides of the bluff body in an alternating pattern wherein these vortices move downstream in two rows. The frequency at which these natural vortices are shed from the bluff body is directly proportional to the fluid velocity in the range of the Reynolds number greater than 1,000 and less than 400,000 and is a nonlinear function of the fluid velocity outside the aforementioned range of the Reynolds number, wherein the Reynolds number is a dimensionless number equal to Ub/V where U is the fluid velocity, b is the width of the bluff body and V is the kinematic viscosity of the fluid. In reality, the bluff body generates and sheds natural vortices in the range of Reynolds number greater than 50 and less than about 10,000,000. Since the vortex shedding frequency is directly proportional to the flow velocity in the range of Reynolds number greater than 1,000 and less than 400,000, the fluid velocity can be determined by measuring the vortex shedding frequency. A flowmeter that measures the fluid velocity by detecting a vortex shedding frequency is called the vortex shedding flowmeter. Vortex shedding flowmeters are widely accepted by today's industry as evidenced by the annual sale of 60 million dollars in 1985. A typical vortex shedding flowmeter of the present day technology includes a bluff body, which is a bar with a blunt cross section disposed perpendicular to the direction of the fluid stream, and means for sensing the vortices shed from the bluff body, which may be a transducer sensing the light force on the bluff body or wing disposed downstream of the bluff body, or transducer sensing the pressure fluctuations caused by the vortices shed from the bluff body. In general, the vortex shedding flowmeters available today measure the fluid flow in the range of Reynolds number greater than 10,000 and less than 200,000, while the operating limit of the vortex shedding flowmeter dictated by the nature is in the range of the Reynolds number greater than 1,000 and less than 400,000. In other words, the present day vortex shedding flowmeters have only 20 to 1 turn down ratio, while the turn down ratio of a perfect vortex shedding flowmeter should have 400 to 1. For the Reynolds number less than 10,000, the fluctuations in the fluid pressure or in the streamlines created by the vortices naturally shed from the bluff body is too weak to be distinguished from the noises transmitted through the pipe wall or through the fluid medium and, consequently, they are too weak to be detected by the present day sensor technology employed in the construction of the existing vortex shedding flowmeters. Typically, the minimum velocity measurable by the existing vortex shedding flowmeter is about 20 to 25 feet per second for air flow under the standard condition and 1 to 2 feet per second for water flow. There are many demands in the industries requiring measurement of gas flows lower than 20 feet per second velocity and liquid flows lower than 1 feet per second velocity. A perfect vortex shedding flowmeter utilizing the full range of feasibility offered by nature should measure gas flows of velocity as low as 2 feet per second and liquid flow of velocity as low as 0.2 feet per second, which velocities are approximately corresponding to the Reynolds number of 1,000. The aforementioned fact indicates that the present state of the art in the vortex shedding flowmeter technology is at an infantile stage and that we have seen only the tip of the iceberg in the versatility and potential application of the vortex shedding flowmeters.